Trajectory calculations are presented for the unimolecular dissociation of HO2. The study covers internal energies in the range 58.311 less than or equal to E-tot/kcal mol(-1) less than or equal to 59.432, just above the H + O-2 threshold, and E-tot = 76.412 kcal mol(-1) for which the O + OH channel is also open. The HO2 single-valued double many-body expansion potential energy surface has been employed in all calculations. Due to strong coupling among the vibrational degrees of freedom, mode specificity is shown to play a minor role in the formation of H + O-2. Conversely, the increase of initial rotational energy clearly influences the dynamics of the unimolecular dissociation. In particular. energy placed in a specific rotational degree of freedom can dramatically modify the yield of O-2 or OH products and corresponding decay rates. The results show the importance of rotational effects in order to correctly describe the unimolecular dissociation of HO2.